This invention relates to sequential decorrelator arrangements such as are used in adaptive antenna arrays to perform beamforming operations.
Adaptive beamforming provides a powerful means of enhancing the performance of a broad range of communication, navigation and radar systems in hostile electromagnetic environments. In essence, adaptive arrays are antenna systems which can automatically adjust their directional response to null interference or jamming and thus enhance the reception of wanted signals. In many applications, antenna platform dynamics, sophisticated jamming threats and agile waveform structures produce a requirement for adaptive systems having rapid convergence, high cancellation performance and operational flexibility.
In recent years, there has been considerable interest in the application of direct solution or "open loop" techniques to adaptive antenna processing in order to accommodate these increasing demands. In the context of adaptive antenna processing these algorithms have the advantage of requiring only limited input data to accurately describe the external environment and provide an antenna pattern capable of suppressing a wide dynamic range of jamming signals.
The objective of an optimal adaptive antenna system is to minimise the total noise residue (including jamming and receiver noise) at the array output whilst maintaining a fixed gain in the direction of the desired signal and hence lead to a maximisation of resultant signal to noise ratio.